Permanent magnet containing nickel, aluminum, and manganese



Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE 2,027,999 PERMANENT MAGNET CONTAINING NICK- EL, ALUMINUM,

AND MANGANESE Tokushichi Mishima, Yodobashi-ku. Tokyo, Japan No Drawing.

Original application January 20,

1932, Serial No. 587,822. Divided and this allplication August 7, 1935, Serial No. 35.208. In Japan August 27, 1931 '4 Claims.

scribed that a so-called "irreversible nickel steel can be changed into a reversible steel" by the addition of aluminum, thereby obtaining a strong magnetic alloy. According to the invention it has been found that the addition of a proper amount of other metals as auxiliary elements will further improve the magnetic properties as well as the tenacity and ductility of the permanent magnet and facilitate the mechanical working of the magnet.

It is well known that the more minute the microstructure of the magnet steels is, the greater is the increase in the number of molecular magnets arranged irregularly at the boundaries of the crystal grains so that consequently the coercive force and they residual magnetism also increase. This feature is galned by the addition of certain amounts of one or more auxiliary metals to the main elements iron, nickel and aluminum in the proportions herein given.

It is often desirable that the new alloy is more easily forged and rolled than the alloys as explained above, so that it may be applied more easilyfor obtaining special magnet steels. For this purpose 0.5 to 10% manganese is added to lie new alloy. It is found that by this means the toughness and ductility of the alloy can be considerably increased, and the mechanical working is made very easy. At the same time a higher coercive force and a stronger residual magnetism can be obtained.

Actual examples for carrying out the invention thus modified are given:

Chemical composition (per cent) Magnetic properties Coercive Residual Alumi- M n auese force (He) etism Iron Nickel num a g (8a (8 17.5 0. 8 2. 150 9,600 l7. 0 9. 5. 0 155 9, 700 01.2 25. 0 l0. 5 3. 0 265 9, 700 54.7 30. 5 l2. 0 2. 5 490 9, 500

From this table it will be seen that themagnetic property is greatly increased. This 18 due to the fact that the manganese added to the alloy makes the crystal grains very fine and consequently increases the number of molecular magnets arranged irregularly at the boundary of the grains. Therefore this alloy may be used for making ordinary permanent magnets, and also in making special magnets required to be finished by complicated and precise working. It is also noted in this case that the presence'of carbon of below 1.5% and/or a small amount of impurities does not materially affect the magnetic properties of the alloy.

I claim:

1. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 10% manganese and the remainder iron.

2. A permanent magnet comprising 5 to 40% nickel, 7 to aluminum, 0.5 to 10% manganese and the remainder substantially iron.

3. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 10% manganese. from trace to 1.5% carbon and the remainder iron.

4. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 10% manganese, from trace to 1.5% carbon and the remainder substantially iron.

TOKUSHICHQfAflSI-IIMA. 

